Concrete Slab Calculator
Enter your slab size and thickness to find out how much concrete you need, either as ready-mix by the truck or as 60 or 80 lb bags. It works for patios, shed pads, walkways and small footings.
Common questions
Should I buy bags or ready-mix?
Choose one. Bags work for small slabs and footings. For larger slabs, often around a cubic yard or more, a ready-mix truck is usually easier.
What bag yield does it use?
An 80 lb bag makes about 0.60 cu ft and a 60 lb bag about 0.45 cu ft. These are typical published yields. Check your bag label.
What is the waste setting for?
It adds extra for uneven ground, spillage and form bulge. The default is 10%, and you can change it.
When should I hire a pro?
Consider one for driveways, large slabs, anything structural, or a pour that needs a pump, rebar layout or a permit.